1. Field of the Invention
The present invention relates generally to communication systems, and is more particularly related to providing fairness in the servicing of queues in a switching communication system.
2. Discussion of the Background
As businesses and society, in general, become increasingly reliant on communication networks to conduct a variety of activities, ranging from business transactions to personal traffic congestion. For example, the maturity of electronic commerce and acceptance of the Internet as a daily tool pose an enormous challenge to communication engineers to develop techniques to reduce network latency and user response times. With the advances in processing power of desktop computers, the average user has grown accustomed to sophisticated multimedia applications, which place tremendous strain on network resources (e.g., switch capacity). Also, because the decrease in application response times is a direct result of the increased processor performance, the user has grown less tolerant of network delays, demanding comparable improvements in the network infrastructure.
Network latency is attributable, in part, to queueing delays. Conventionally, queueing delays are difficult to predict or bound, in part, because of the correlation between the output traffic and the input traffic, which can exhibit a wide variety of behaviors (e.g., stochastic, deterministic, or a combination thereof). As a result of the inability to readily determine an upper bound on the queueing delay, applications cannot efficiently determine a timeout period for retransmitting lost or greatly delayed packets. Without accurate knowledge of the upper bound, the end users are unable to receive a guarantee on their application response times. To further exacerbate the increased response times, the delays are not uniform across the users; that is, some users, by virtue of the relative position of the queues that store their traffic, may experience significantly more delay than other users. Thus, the queues are not serviced fairly during network congestion, for example.
One traditional approach to minimizing queueing delays is to upgrade the hardware to increase capacity—e.g., processing power. The main drawback with this forklift approach is cost. Further, in some systems, such as a communication satellite, hardware replacement is impractical.
Based on the foregoing, there is a clear need for improved approaches to minimizing queueing delay.
There is also a need to optimize the use of existing network hardware.
There is also a need to determine an upper bound of the worst-case queueing delays.
Based on the need to improve system throughput, an approach for providing fairness by minimizing queueing delays is highly desirable.